Method for producing electric lamps



March 20, 1934'. 1 A KORENGOLD 1,951,423

METHOD FOR PRODUCING ELECTRIC LAMPS Filed April 10, 1933 IN VEN TOR.

S5:- BY/w?. I

ATTORNEY.

UNITED sTATEs PATENT OFFICE METHOD FOR PRODUCING ELECTRIC LAlWPS John A. Korengold, Chicago, lll. Application Aprilia, 193s, serial No. 665,252

5 Claims.

My presentinvention relates to a method for producing the type of electric lamps which are employed for illuminating oral and other cavities. Such lamps generally comprise a small electric light .bulb mounted in the end of a glass tube which end has previously been closed and sealed by fusion. The tube is of relatively small diameter and of suicient length to'introduce it into the cavity the required distance.

from the bulb are carried through the bore of the tube with suitable provision for spacing them from one another and the tube is usually provided with a packing about the conductors. At the end of the tube opposite to that which contains the light a lamp plug is attached to the tube and the conductors are united with the terminals thereof. Such an apparatus, no matter how carefully made, is fragile and ithas been sought for some time to provide such thin elongated electric lamps from other materials than glass, but this has heretofore proved diflicult as the lamps have to be sterilized, usually by immersion in hot liquids or liquids rendered antiseptic by the admxture of some chemical therewith.

' It has heretofore proved to be impossible to seal the electric light bulb in the end of a metal tube in such a manner that the liquids employed in the sterilizing of the lamps would not enter between the stem casing and the electric light bulb. A metallic lamp is peculiarly desirable if it can be produced in that it is least liable to break and is more easily and dependably sterilized, and another feature of a metallic lamp is that it prevents the transmissi on of light through the walls of the stem and a back glow which operates to decrease and interfere with the illumination which would otherwise be obtainable.'

My present process or method relates to the provision of such rod-like lamps which will dependably exclude fluid from entering the tube in which the light bulb is installed and which also will obviate the necessity of providing an additional socket element to such lamps.

I have illustrated the manner of employing my method in the accompanying drawing, in which- Fig. 1 is a side view or elevation of a lamp produced by the practice of my method.

Fig.2isa

structure shown in Fig. 1,

Fig. 4 is a central,

to Fig. 2 illustrating necessary when a gl central, longitudinal section of the drawn to an enlarged 3 is a perspective of an incandescent light the production of the lamp.

longitudinal section similar the changes in arrangement ass tube is employed; and- The conductors y Similar reference characters refer to similar parts throughout the respective views.

My method includes the provision of a tube 10 preferably formed of a non-corroding alloy, several of which alloys may be obtained upon the market. I have illustrated the tube 10 with a circumferential bead 10a provided therein ama- 'cent the end of the tube in which the bulb is mounted which not only adds an element of decoration to the lamp but may also be of advantage in the use of the'lamp. The reduction of the bore of the tube 10, by means of the bead 10a,.serves to delay and retard the application of pressure as the filling compound is being forced in about the bulb, which is a desirable feature as this constitutes the critical stage in the practice of my method in producing lamps.

The tube 10 is selected of a size to provide a. bore within which' a diminutive light bulb 11 may be inserted. Upon one end of the tube 10 is provided a small inwardly inclined ange 12 which will be of suflicient size to prevent the passage of the light bulb 1l through the end provided with the flange. The light bulb 11, except for its size, is of ordinary construction, having enclosed therein a filament 13 with the leads or conductors 'from the filament passing through the walls of the bulb and fused therein in the ordinary manner. To one of the leads or conductors which extend through the walls of the bulb I attach a piece of thin sheet metal 14 which is bent forward to lie adjacent the walls of the bulb. To the other lead or conductor passing through the walls of the bulb 1I secure a metal rod 15 of relatively large diameter which, will traverse the bore of the tube without filling all of the space therein, and which will not touch the walls of the tube when properly positioned in the bore thereof. The rod 15 is of suitable length to extend for a distance from the end-of the tube opposite to that upon which the flange 12 is provided and in which the lamp bulb 11 is pomolded by employing coincidently heat and pressure and my present method differs from the ordinary practice in that instead of heating the bakelite under pressure I rst heat the same until sufficient plasticity has been obtained and then force the plastic heated bakelite into the tube 10 through the end from which the rod 15 projects. l

I have found thata degree of plasticity of the bakelite can be readily secured which will be effective to force the lamp bulb 11 against the flange 1'2 with any degree of force Whichmay be desired. This forcing of the lamp bulbl 11 against the flange 12 will also secure the forcing of the piece of sheet metal l14 into extremely intimate contact with the interior wall of the flange 12 and the tube 10. The process of forcing the plastic bakelite into the tube 10 is continued until an exudation of the bakelite is observed. around the edges of the flange, at which time the increasing of the pressure is stopped and the structure is permitted to cool. After the bakelite is cooled and solidifiedv it is trimmed from around y the extending end of the rod 15 so as to be flush vwith my lamp.

with the end of the tube 10. The rod is then cutto a desired length and preferably split, as at '16, when it serves as the central terminal for thelamp bulb, the tube itself constituting the other terminal for the lamp bulb so that no separate or additional plug structure need be formed Such a method of preparing lamps may be employed to advantage with a glass tube 17, as shown inFig. 4, instead of a metal tube, and in such a, case the fragility of the structure will be considerably decreased. In such a case, however, a second conductor must be provided within the tube by splitting the rod 15 so as to attach the portions thereof with the conductors from the lamp. The metal ,tube, however, heretofore described, seems at present to be the preferable structure.

I have illustrated my lamps in the form of a straight cylinder, as shown in Figs. 1, 2 and 4, and also in the form of a cylinder having a right angularextension 18 in which the light bulb is mounted, as shown in Fig. 5.

-Having described my invention what I claim as new and desire to secure by Letters Patent is:

1. An electric lamp comprising a metal tube inwardly Vflanged at one end, an electric light bulb and a metallic rod, one conductor from said bulb being secured to vsaid rod and the other conductor from said bulb being bent parallel with the body of said bulb, said bulb being placed within said tube against the ange at the end thereof and with the bent back conductor in contact with, said tube and with said rod disposed axially Within but out of Contact with Said tube ductors and rod.

4. An electric lamp comprising an electric' and extending from the unflanged end thereof and compressed bakelite filling the spaces within saidA tube not occupied` by said bulbfconductors and rod.

- 2. An electric lamp comprising a metal tube inwardly flanged at one end, an electric light bulb and a metallic rod, one conductor from said bulb being secured to said rod and the other conductor from said bulb being disposed to contact said tube when placed therein, said bulb being placed within said tube against the flange at the end thereof and with said rod disposed axially -within but out of contact with said tube and extending from the unflanged end thereof andl compressed bakelite lfilling the spaces within said tube not occupied by cast insulating composition filling the spaces' within said tube not occupied by said bulb, conbulb, one conductor whereof is secured 'to a metallic rod and the other conductor whereof is provided with a strip of sheet metal, a metal tube having an inwardly flanged end within which tube and against which flange is positioned'said `electric bulb with said rod extending axially of said tube and out of contact therewith and beyond' the opposite end thereof, said strip of sheet metal being positioned between said bulb and the inner walls. of said tube, and a fusible insulating material which solidifles at temperatures substantially above that of boiling water compacted into said tube so as to force said strip of metal into contact with the inner walls of said tube and s maintain the other elements in thev above described relation.

5. The method of producing electric lamps comprising the heating of condensate in a pulverulent state and the forcing of such heated mass into a flanged tube containing an electric light bulb, whereby said bulb is seated against said flange by the entry of said condensate and maintained in such relation upon the cooling andsolidifying thereof.

JOHN A. KORENGOLD 

